Reciprocating engine



Oct. 5, 1,943. J. T. BIRD lvixcI'PRocATING ENGINE 2 Sheets-Sheet 1 Fi'led Sept 4. 19,41

Oct 5, 1943. J. T. .BIRD

RECIPROGATING ENGINE Filed sept. 4, 1941- 2 sheets-shet 2.

y v Zzvenzr jms Tkamaa Bird f piston engines. Y

Patented Oct. 5, 1943 UNITED? r :REcIraooATINGnNGmn y,ifguiles' 'rh-amas Bird, London, la'iigiainll f f Application september 4,1941,se`ria1No.4o9,438 f "Thr Great Britain February 13,1941 1 1 e. met

i `This invention relatesto reciprocatingengines and, while directed 'partioularlytothe'provision of an improvedV internal Y 'combustionl `high speed i prime mover, yisv also applicable/to compressors and pumps.

stearrengines,

Engines having'a plurality of Iop'posedllpistons with combustionv spaces between-them in coaxial `alignment"have .been proposed and r'patented in the past. A l sv y f Y These engines if properly-constructed willhave advantages in saving in material, weight'Y and space, which is due in lthemain to afsubstantially reduced size of the crankcase, vthe balanced reciprocating Weights, and the return of the latter by combustion Yimpulse in each direction of the piston travel, which characteristic practically relleves the crankshaft of pressure dueto reciprocating parts or differences in cylinder'pressure. Other advantageous points are-the reduced loading of bearings, the parallel motion ofithepistons and piston couplinglrods and the greatly reduced piston friction resulting therefrom, the halving of piston speed and travel, and consequently, of the crankthrow for any ygiven effective kstroke resulting 'in lower inertia forces;Y and the lightand symmetrical castings, andadditional known advantages commento all swift acting opposed- Engines -of the type previously proposed suffered from defects and difliculties in constructionand working which have hitherto rendered them' unattractive to manufacturers and users alike. l i f The object of my invention- Ais to avoid such undesirable stresses, complications', Vand dimen- V sions in the construction of enginesof vthe above type, while attaining a definite formv of'construction' which is *both eflicient in working and capable of commercial production.v

In accordance with the present invention an engine ofthe type above referred to has' necks attached to the pistonsand gudgeons or cross /beams passing through these necks ar connected lto coupling rods on each side of the pistons, these coupling rods` being parallely to the axis ofr the pistons and having means for converting their reciprocating motion into rotation of the engine shaft, o K

In the preferred form-of engine according to this invention, the gudgeons or cross-beams of the pistons, which form a rigid `frame' with their respective coupling rods,fare made as light 'and short as lpossible bylocatingthe piston coupling rods close tothe cylinder. This maybe effected by recessingl or Vflattening the cylinder castingto Y"the cylinder as practicable.

accomodate the longer pair of rods, or by placing one pair of rods within the other, or by crossing the two sets of gudgeons at right angles so that both pairs of rods may be located as knear to In one arrangement each combustion chamber or cylinder part has two pistons which move in opposite' directions and, with the exception of the end pistons, each piston is connected to'a piston of the next combustion chamber or cylv inder part, andthe two crows of the double piston are connected by a neck or skirt. l

The pistons have transverse gudgeons der, parallel to the axis thereof and forming with VtheV gudgeons -a rigid frame which moves vin a straight line and prevents sideways forces on the pistons tending yto induce slap.

With' this arrangement the recipricating parts are balanced and are cushioned at the end of -their strokes by compression and combustion.,

pressure which occurs simultaneously in each direction of the piston travel; moreoverdue vto the push and pull exerted byone combustion impulse nocounterbalancing of the crank-shaft is necessary.

Compared with the ordinary engine the stroke and piston speed are halved thus greatly reducing inertia forces in spite of increased mass of reciprocating parts.

In the accompanying drawings which illustrate the invention in a diagrammatic manner:

Fig. 1 represents a four-strike internal comf bustion engine having five pistons,

Fig. '2 represents `a central-section through a two stroke engine, l i l Fig. 3 represents a sideview partly in section of the engine shown in Fig. 2 with the pistons in a different position.

Referring rstto Fig. 1 there are ve .pistons threeof them, I, 2, 3 being double pistons' con-A nected by necks'll, 5, Gand the outer pistons 1 8 bein'gsingle pistons with necks, 9, I0. Transverse gudgeons II, I2, I3', I4', through the necks of these pistons.-

These gudgeons are vconnected to coupling rods I6, I1, I8, I9 two oneach side of the engine; the outer and central gudgeons connect to the inner rods I6,` II and the other two to the outerrods I8, I9 the rods IS,` I1A having slots 20, 27|, 22, 23 sothat the budgeons I2, I4 may pass through them.V Y

These coupling rods are connected'by short y connecting-rods 24, 25,126,` 21 to cranks 28, 29,

'con-i. nected to cross-heads at each side of the cylin- I 5 -pass The cylinders A, B, C, D have no covers and have slots E, F, G, H, J through which the gudgeons pass.

Referring now to the engine shown in Figs. 2 and 3 of the drawings there are two single pistons 'I, 8 and one double piston I arranged between them. The neck 4 connecting the two parts of the piston I is in the form of a. partial skirt suiiciently wide to seal slots F through which pass the gudgeon I2; this gudgeon is connected to coupling'rods I8, I9, preferably in the form of hollow tubes, and thence through short connecting rods 24 to cranks on the engine shaft 32.

The gudgeons II, I are connected to coupling rods IB', II which are slotted to allow the gudgeon I2 to pass through and short connecting rods 25 transmit rotary motion to cranks on the shaft 32 The innermost cross-heads may be connected to a single crank so that the engine has three cranks. l

With this construction of engine the crankshaft is practically relieved of pressures due to reciprocating parts, or diiierences in cylinder pressure.

The portion of the cylinder housing the double-piston is surrounded by an annular air chamber K in direct communication with the inlet ports L, which allows the combustion air to flow into the combustion space every time the inlet ports are uncovered bythe piston crowns. This fresh air which may be supplied by a blower or pump M, does not only constantly enter Athe annular chamber but also the piston interior. The latter thus functions as an additional air receiver and is automatically and continuously cooled by fresh combustion air, which is preheated simultaneously on its way into the cyllne inlet ports L are located at or near the tops of the centre double-piston in its respective dead centre position whereas the exhaust ports N are located at the other ends of the combustion chamber at ornear the tops of the top andbottom single pistons in their respective dead centre position. This arrangement benefits the uniow swirl of the fresh Vcombustion air through the cylinder.

The top and. bottom single pistons are aircooled by their undersides, skirts or stems R, and gudgeons being exposed to the free flow of fresh air, which is sucked in and pushed out by the action of the piston through suitable slots and/or liandholes in the cylinder casting.

VJith this engine it is possible to introduce separate lubrication for crankcase and cylinder and to avoid forced ,mechanical lubrication to any part of the engine.

Cylinder lubrication independent of crankshaft lubrication may be provided by placing a reservoir P of cylinder oil in communication with the outlet side of the pump or blower for air M or of the exhaust gas pressure.

In the case of heavy oil engines the fuel may be injected direct to the cylinders; for petrol or gas engine the explosive mixture may be delivered by the pump or blower.

It will be understood that the invention is not restricted to the details of the speciic embodiment described which may be varied without departing from the broad idea underlying it.

I claim:

1. A reciprocating engine having in combination a plurality of coaxial pistons, necks attached the engine shaft.

to said pistons, gudgeons passing transversely through said necks, coupling rods connected to said gudgeons on each side of said pistons, said coupling rods being parallel to the axis of said pistons, and means for transmitting their reciprocating motion to the engine shaft.

2. A reciprocating engine having in combination two pistons and a double piston between them in axial alignment,l necks attached to said pistons, gudgeons passing transversely through said necks, coupling rods connected to said gudgeons on each side of said pistons, the gudgeons of the end pistons being connected to one pair of coupling rods parallel to the axis of the pistons and the gudgeon of the double piston being connected to another pair of coupling rods parallel to the axis of the pistons and means for transmitting their reciprocating motion to the engine shaft.

3. A reciprocating engine having in combination; two pistons and a plurality of double pistons between them in axial alignment, necks attached to said pistons, gudgeons passing transversely through` said necks, coupling rods connected to said gudgeons on each side of said pistons, the gudgeons of one set of alternate pistons being connected to one pair of coupling rods parallel to the axis of the pistons and the gudgeons of the other set of alternate pistons being connected to another pair of coupling rods parallel to the axis of the pistons and means for transmitting their reciprocating motion to the engine shaft.

4. A reciprocating engine having in combination two pistons and a double piston between ,them in axial alignment, a partial skirt connecting the pistons of said double piston, a gudgeon passing through said skirt transversely to the axis of said piston and passing through slots in the cylinder in which said double piston reciprocates, said skirt closing said slots and means for transmitting the movement of the pistons to the engine shaft.

5. A reciprocating engine having in combination two pistons and a double vpiston between them in axial alignment, a blower for pumping air into the space between said double pistons, a reservoir for cylinder oil in communication with the outlet side of said blower and means for transmitting their reciprocating motion to 6. A reciprocating engine having in combination two pistons, six pistons coupled together in pairs between the said pistons and in axial alignment therewith, a common cylinder in which said pistons reciprocate, transverse members attached to said pistons, slots in said cylinder in which said transverse members reciprocateand means for transmitting their reciprocating motion to the engine shaft. Y v

'7. A reciprocating engine having in combination a cylinder, two pistons and a double piston in axial alignment operating in said cylinder, an annular space in the cylinder surrounding the double piston, means for introducing the cylinder charge under pressure into f said annular space, and means for transmitting their reciprocating motion to the engine shaft.

8. A reciprocating engine having in combination a cylinder, two pistons and a double'piston in axial alignment operating in said cylinder a partial skirt connecting the two crowns of said I double piston, an annular receiving space in the cylinder surrounding and in direct connection with the interior of the double piston, means for' into said combined receiver space and means for transmitting their reciprocating motion to the engine shaft.

9. A reciprocating engine having in combination a cylinder, two pistons and a double piston in axial alignment operating in said cylinder, a partial skirt connecting the two crowns of said double piston, an annular receiving space in the cylinder surrounding and in direct connection with the interior of the double piston, a blower or pump introducing the cylinder charge into said combined receiver space and means for transmitting their reciprocating motion to the engine shaft.

10. A reciprocating engine having in combination a cylinder, two pistons and a double piston in axial alignment operating in said cylinder a partial skirt connecting the two pistons of said double piston, an annular space in the cylinder surrounding the double piston, means for introducing air under pressure into said annular space and means for transmitting their reciprocating motion to the engine shaft.

Y 3 ll. A reciprocating engine having in combination a cylinder, two pistons and a double piston in axial alignment operating'in said cylinder a partial skirt connecting the two pistons of said double piston, an annular space in the cylinder surrounding the double piston, a blower introducing air under pressure into said annular space and means for transmitting their reciprocating motion to the engine shaft.

y12. A reciprocating engine having in combination a cylinder, two pistons and a double piston in axial alignment operating in said cylinder, a partial skirt connecting the two pistons of said double piston, an annular space in the cylinder surrounding the double piston, means for introducing air under pressure into said annular space, means for passing said airinto the cylinderV spaces between the pairs of pistons and means for transmitting their reciprocating motion tothe engine shaft. l

JAMES THOMAS BIRD. 

